Same here, traffic. My work is about 5 miles in a straight line down the busiest street in the west San Fernando Valley (Los Angeles County), and passes under a major freeway on/off ramp. My first commute was scary, and quite a learning experience.
I do ride a road bike, and choose less traveled streets when possible, as this part of the Valley has few dedicated bike lanes, and always has lots of impatient traffic.
But I have never rode in the dark before starting commuting two years ago.
So I decided to not wade in the kiddy pool, but jump in the deep end as I know how to swim already and just have fear. I bought a front and rear light, attached them to my MTB, and set off right after the New Years break, into the darkness.
First lesson I learned the hard way; buy enough light. I can't see squat with my AA front light. A little education, and now I have a 600 lumen rechargable front light. Lost the rear light, and the next, when the mount broke. They ate AAs like water anyway, so now I have a rechargable rear blinkie that is as bright as a car brake light and mounted with a stout bracket. Bought a dedicated commuter, added reflective tape, mounted the lights.
Guess that's been my comfort. Be as visible as possible. The lights and reflective tape are your best defense. That is a part of what I used to get over the fear.
I also analyzed the route, especially where it crosses under the freeway as that is a very busy spot. Decided to 'take the lane', the far right lane, as there is no room for a bike on the right side. I stop at the light, before the freeway, in the right lane. Anyone coming up behind me can choose the left lane, or get behind and to the right of me to get on the freeway on ramp. I have a blinking 150 lumin light on my helmet, that I use to make myself visible to the cars on the offramp that can make a right right into me if I am not careful. From there, I actually have enough room to stay between the parked cars and the right lane, about 4 to 5 feet wide, but that first major intesection followed by the freeway needed some thought to come up with the safest way to cross.
So that would be my second suggestion, right after analyzing what you need to be as visible as possible and make the road visible; look at the route, identify the tricky spots and the safest way to handle them.
You might want to ride the route on your day off, just to see how it goes. You can abort and go home if it is too tricky or outside your comfort zone (I did this too).
Take a look at what you need to take to work. Do you want to lug food, a change of clothes? I take the car on Monday, and take a week's worth of food so that's one less thing to lug. I can then use a backpack for clothing (tried the rack and panniers, but did not like the extra weight on an already heavy bike).
I know others who have commuted for far longer than I will be along shortly with great suggestions. I got the nerve to do it from others here.
Tzvia- rollin' slow...
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